Trace element levels in mollusks from clean and polluted coastal marine sites in the Mediterranean, Red and North Seas

The trace element contamination levels in mollusks were evaluated for diffe rent marine coastal sites in the Mediterranean (Israeli coast), Red (Israel i coast) and North (German coast) Seas. Three bivalve species (Mactra coral lina, Donax sp, and Mytilus edulis) and two gastropod species (Patella sp. and Cellana rota) were sampled at polluted and relatively clean sites, and their soft tissue analyzed for Hg, Cd, Zn. Cu, Mn and Fe concentrations. Re presentative samples were screened for organic contaminants [(DDE), polychl orinated biphenyls PCBs and polycyclic aromatic hydrocarbons (PAHs)] which exhibited very low concentrations at all sites. In the Red Sea. the gastrop od C. rota showed low levels of Hg (below detection limit) and similar Cd c oncentrations at all the examined sites, while other trace elements (Cu, Zn , Mn, Fe) were slightly enriched at the northern beach stations. Along the Mediterranean coast of Israel, Hg and Zn were enriched in two bivalves (M. corallina and Donax sp.) from Haifa Bay, both species undergoing a longterm decrease in Hg based on previous studies. Significant Cd and Zn enrichment was detected in Patella sp. from the Kishon River estuary at the southern part of Haifa Bay. In general, Patella sp. and Donax sp, specimens from Hai fa Bay exhibited higher levels of Cd compared to other sites along the Isra eli Mediterranean coast, attributed to the enrichment of Cd in suspended pa rticulate matter. Along the German coast (North Sea) M. edulis exhibited hi gher concentrations of HE and Cd at the Elbe and Elder estuaries, but with levels below those found in polluted sites elsewhere.